A hologram recording/reconstructing apparatus includes a spatial modulator in which a reference beam region and a reconstruction beam region are formed, and a controller configured to control a range of the reference beam region and a range of the reconstruction beam region. According to a temperature of a hologram recording medium during recording, the controller sets the range of the reference beam region to a first predetermined range and thereby sets a range of an incident angle of a reference beam on the hologram recording medium to a first predetermined angle range. According to a temperature of the hologram recording medium during reconstruction of recorded data, the controller sets the range of the reconstruction beam region to a second predetermined range and thereby sets a range of an incident angle of a reconstruction beam on the hologram recording medium to a second predetermined angle range.